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<span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">Dear all,</span><br>
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I'm interested in identifying sources of the EEG evoked components I get in the grand average, and I'm not going to apply further statistical analyses on sources. </div>
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<span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">I followed the Fieldtrip tutorial for source reconstruction of MEG event-related fields (http://www.fieldtriptoolbox.org/tutorial/minimumnormestimate/), which is on data
from a single subject, and I'm not sure about how to proceed at the group level. </span><br>
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<span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">I concatenated all trials from </span><span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">all subjects to calculate the covariance and
computing the grand average with "ft_timelockanalysis". </span></div>
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<span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">First, is this an appropriate way to apply mne method in "ft_sourceanalysis" at the group level?</span><br>
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<span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">Moreover, </span><span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">I was looking for a good way to check</span><span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt"> </span><span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">the
results I obtained, for example by applying another method, such as beamformer. </span>Is it reasonable to think that the two methods would lead to comparable results on time-locked data?</div>
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<span style="margin:0px">If yes, how can I apply the beamformer method </span>in "ft_sourceanalysis"? I replaced the cfg.method field (mne with l<span style="margin:0px; background-color:rgb(255,255,255); display:inline!important">cmv)</span>, but the output
I get does not contain information about time. <span style="margin:0px"><br>
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<span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">Here's the code I used. </span><span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">I don't have individual MRIs, thus I am using templates
for the headmodel (standard_bem) and the sourcemodel (cortex_5124.surf.gii). </span></div>
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<span style="font-family: Calibri, Helvetica, sans-serif, serif, EmojiFont; font-size: 12pt;">---</span><br>
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<span style="margin:0px">% create a preprocessed structure<br>
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<div style="margin:0px"><span>cfg =[];<br>
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<div>cfg.channel = {'EEG'};<br>
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<div>cfg.demean = 'yes';<br>
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<div>cfg.baselinewindow = [-0.1 0];<br>
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<div>data_prepr = ft_preprocessing(cfg, data_long);<br>
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<div><br>
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<div>cfg =[];<br>
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<div>cfg.covariance = 'yes';<br>
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<div>cfg.channel ={'EEG'};<br>
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<div>cfg.covariancewindow = [0 0.4];<br>
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<div>data_tlck = ft_timelockanalysis (cfg, data_prepr);<br>
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<div><br>
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<span></span></div>
<div style="margin:0px">% forward solution [prepare leadfield]<br>
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<span>cfg = [];<br>
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<div>cfg.elec = elec;<br>
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<div>cfg.channel = {'EEG'};<br>
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<div>cfg.headmodel = vol; % volume conduction model<br>
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<div>cfg.grid = ft_read_headshape('cortex_5124.surf.gii');<br>
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<div>cfg.grid.pos = sourcemodel.pos;<br>
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<div>cfg.grid.inside = 1:size(sourcemodel.pos,1); % all source points are inside of the brain<br>
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<span>leadfield = ft_prepare_leadfield(cfg);</span>
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<div style="margin:0px">% inverse solution (method: mne)<br>
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<span>cfg = [];<br>
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<div>cfg.method = 'mne'; %'lcmv';<br>
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<div>cfg.elec = elec;<br>
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<div>cfg.channel = {'EEG'};<br>
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<div>cfg.grid = leadfield;<br>
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<div>cfg.headmodel = vol;<br>
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<div>cfg.mne.prewhiten = 'yes';<br>
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<div>cfg.mne.lambda = 3;<br>
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<div>cfg.mne.scalesourcecov = 'yes';<br>
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<div>source_bial_mne = ft_sourceanalysis(cfg, data_tlck);<br>
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<div style="margin:0px">%%plot<br>
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<div style="margin:0px">bnd.pos = sourcespace.pos;<br>
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<div style="margin:0px">bnd.tri = sourcespace.tri;<br>
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<div style="margin:0px">m=source_bial_mne.avg.pow(:,124); % point in time I want to plot<br>
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<span style="margin:0px">figure; ft_plot_mesh(bnd, 'vertexcolor', m);</span><br>
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Any help would be really appreciated, t<span style="font-family:Calibri,Helvetica,sans-serif,serif,EmojiFont; font-size:12pt">hanks in advance!</span></div>
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Best,</div>
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Agnese</div>
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<div style="color:rgb(34,34,34); font-family:Arial,Helvetica,sans-serif; font-size:small; background-color:rgb(255,255,255)">
<span><span><font color="#666666">Agnese Zazio, PhD Student</font></span></span><br>
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<div><b><font color="#666666">Cognitive Neuroscience Section,</font></b></div>
<div><font color="#666666"><b>IRCCS Saint John of God Clinical Research Centre </b>
(Brescia, Italy)<br>
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